In MongoDB, the db.collection.unhideIndex() method unhides a hidden index.
A hidden index is one that’s hidden from the query planner. When you unhide an index, it is no longer hidden from the query planner, and it’s immediately available for use.
Continue readingMongoDB introduced the db.collection.hideIndex() method in MongoDB 4.4.
This method hides an existing index from the query planner. This allows you to evaluate the potential impact of dropping an index without actually dropping the index.
If hiding it has a negative impact, you can use db.collection.unhideIndex() to unhide the index. This saves you from having to drop the index, then recreate it.
In MongoDB, you can create an index on a collection using the createIndex() method, the createIndexes() method, or the createIndexes administration command.
There are several ways to create an index in MongoDB, and from MongoDB 4.2, we can create wildcard indexes.
A wildcard index can be thought of as a kind of filter that automatically matches any field, sub-document or array in a collection and then indexes those matches.
Continue readingIn this article I outline two ways to return a list of indexes in an SQLite database.
The first (and most obvious) method is to use the .indexes dot command. The second method is to query the sql_master table.